pipex - @42Wolfsburg

description

pipex takes the project aimed to better understand shell redirection and pipes, by handling them in C.

the program takes an input file, performs a command on it, pipes the result to another command which then writes its result to an output file.

program's arguments are processed the same as < infile cmd1 | cmd2 > outfile in shell.

the result copiesthe output of this shell command: $ < input_file command1 | command2 > output file

here are some resources i used:

• creating and killing child processes in c

• pipe: an inter-process communication method

• handling a file by its descriptor in c

• a comprehensive guide to pipex

# ./pipex infile cmd1 cmd2 outfile
pipe()
 |
 |-- fork()
      |
      |-- child // cmd1
      :     |--dup2()
      :     |--close end[0]
      :     |--execve(cmd1)
      :
      |-- parent // cmd2
            |--dup2()
            |--close end[1]
            |--execve(cmd2)
 
# pipe() sends the output of the first execve() as input to the second execve()
# fork() runs two processes (i.e. two commands) in one single program
# dup2() swaps our files with stdin and stdout

usage

1. clone this repository: git clone git@github.com:idleira/pipex.git pipex && cd pipex

2. use make to compile the project

3. run the program with shell commands in this order: ./pipex <infile> <cmd1> <cmd2> <outfile>

my final grade